ICTV Virus Taxonomy Profile: Adnaviria 2025.

Abstract

Viruses assigned to the realm Adnaviria have linear, dsDNA genomes in which the DNA is structured in the A-form rather than the usual B-form. Virions are flexible or rigid filaments, with or without envelopes. Adnavirians share homologous major capsid proteins (MCPs) with a distinct α-helical structural fold not observed in other known viruses. The MCPs form homodimeric or heterodimeric capsomers that wrap around and condense the genomic dsDNA into helically symmetrical virions. Adnavirians infect hyperthermophilic, thermoacidophilic and methanotrophic archaea. This is a summary of the International Committee on Taxonomy of Viruses Report on the realm Adnaviria, which is available at ictv.global/report/adnaviria.